From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS, URIBL_BLOCKED,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9D9C6C43441 for ; Thu, 29 Nov 2018 18:31:50 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 7655D21104 for ; Thu, 29 Nov 2018 18:31:50 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="oCb2I/xT" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7655D21104 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=BElm6Tt2AYEFn9N1WxO6+v72eKquqUaxosDQXm4jW9c=; b=oCb2I/xTGcH/pI ljN3NYxqXu6NPym+0L7RuVbmrgg1aaO24zBi2otNVt9/ep1ccqc8Py6OW4tl0R/tPMLQ0+x2HBlXY zoaiUgVT11M2JLOKzArUY5ptdBGButb981tILrK7C/102jSNqNiOIC/B5orRDTGblJslnLd3v5BMK Oe/JeKaxWa+S/QB25YpSY9yY9Kl831oT7FgwzmqYKhOmDNV/PrLzIeJwR3evDbl8ioQl/IQXvW540 azLg39jfrz/Xu0pUf2KeakGzAxuyy1KM2aUrEkftXZv/KAK2j2wn1/Fo782lay0t5a8ZADUbq84Xx VvevrVxVq+DFDIpD8yTw==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1gSR6J-0003MR-2t; Thu, 29 Nov 2018 18:31:47 +0000 Received: from verein.lst.de ([213.95.11.211] helo=newverein.lst.de) by bombadil.infradead.org with esmtps (Exim 4.90_1 #2 (Red Hat Linux)) id 1gSR6G-0003CT-Jk for linux-arm-kernel@lists.infradead.org; Thu, 29 Nov 2018 18:31:46 +0000 Received: by newverein.lst.de (Postfix, from userid 2407) id B667068BDF; Thu, 29 Nov 2018 19:31:32 +0100 (CET) Date: Thu, 29 Nov 2018 19:31:32 +0100 From: Christoph Hellwig To: Linus Torvalds Subject: Re: remove the ->mapping_error method from dma_map_ops V2 Message-ID: <20181129183132.GA30281@lst.de> References: <20181123065511.GA17856@lst.de> <20181128074117.GA21126@lst.de> <20181128174545.GJ30658@n2100.armlinux.org.uk> <20181128180841.GM30658@n2100.armlinux.org.uk> <20181129162323.GA27068@lst.de> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.17 (2007-11-01) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20181129_103144_795302_BD9F9E5C X-CRM114-Status: GOOD ( 11.33 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-arch@vger.kernel.org, linux-ia64@vger.kernel.org, linux-parisc@vger.kernel.org, David Woodhouse , the arch/x86 maintainers , Russell King - ARM Linux , Linux List Kernel Mailing , iommu@lists.linux-foundation.org, linux-alpha@vger.kernel.org, xen-devel@lists.xenproject.org, robin.murphy@arm.com, Christoph Hellwig , linux-arm-kernel@lists.infradead.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Thu, Nov 29, 2018 at 09:44:05AM -0800, Linus Torvalds wrote: > No. Really. If there's no iotlb, then you just mark that one page > reserved. It simply doesn't get used. It doesn't mean you suddenly > need a swiotlb. Sure, we could just skip that page entirely based on dma_to_phys. > But whatever. It's independent from the patch series under discussion. > Make dma_mapping_error() at least return a real error (eg -EINVAL, or > whatever is the common error), and we can maybe do this later. Ok, I'll do that. > Or, better yet, plan on removing the single-page dma mappign entirely > at a later date, and make the issue moot. What would be the replacement? Build a S/G list for every single page mapping? Not sure that would create a lot of happy campers.. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel